Epoxy resins are thermosetting epoxide polymers that undergo polymerization and cross-linking when exposed to curing agents, such as primary or secondary amines. Applications for epoxy resins are extensive and include general-use industrial applications, as well as high-performance applications in the automotive and aerospace industries.
The usefulness of epoxy resins in many engineering applications is often limited by their brittle nature. Several approaches that have been taken to enhance the toughness of epoxy resins include: chemical modification of the epoxy backbone to produce a more flexible structure; increasing the molecular weight of the epoxy resin; lowering the cross-linking density of the epoxy matrix; incorporation of a dispersed toughener phase in the cured polymer matrix; and, incorporation of inorganic fillers into the neat resin.
Despite the above efforts to enhance the toughness of epoxy resins, there is an ongoing need for additional ways to overcome the inherent brittleness of cured epoxy resins.